Degradation of 3-chlorobenzoate and phenol singly and in mixture by a mixed culture of two ortho-pathway-following Pseudomonas strains.
The compatibility and efficiency of two ortho-cleavage pathway-following pseudomonads viz. the 3-chlorobenzoate (3-CBA)-degrader, Pseudomonas aeruginosa 3mT (3mT) and the phenol-degrader, P. stutzeri SPC-2 (SPC-2) in a mixed culture for the degradation of these substrates singly and simultaneously in mixtures was studied. Another phenol-degrading strain, Pseudomonas sp. SoPC-5 (SoPC-5) that utilizes a meta-cleavage mode also was tried in co-culture with 3mT. The former combination was found to be a better degrader of both the substrates when present alone. But, with inoculum levels of 0.15 mg cell dry wt each of 3mT/SPC-2 or 3mT/SoPC-5 growth with 2 mM each of 3-CBA and phenol was slow with a lag of 24 h and degradation being incomplete. However, with higher inocula in the ratios 1:1, 1:2, and 2:1, i.e., 0.3 + 0.3, 0.3 + 0.6, and 0.6 + 0.3 mg cell dry wt of 3mT and SPC-2, respectively complete degradation of both the substrates occurred. Degradation of 3-CBA was complete with the release of stoichiometric amounts of chloride (Cl(-)) when concentrations of phenol/3-CBA were varied as 2:2, 2:4, and 4:2 mM, i.e., even when the concentration of the more toxic co-substrate 3-CBA was higher than phenol effective simultaneous degradation occurred at the inoculums ratio of 1:1 (0.3 mg dry cell wt. of each strain). These studies clearly indicated the better suitability of ortho-cleavage-utilizing strains as partners in a mixed culture than those follow different modes.
Jayachandran
V P
VP
Department of Food Microbiology, Central Food Technological Research Institute (CFTRI), Mysore, 570 013, Karnataka, India. jaibiochand@yahoo.com
Kunhi
A A M
AA
D001431:Bacteriological Techniques / Q000379:methods*; D001673:Biodegradation, Environmental; D001709:Biotechnology / Q000379:methods*; D002723:Chlorobenzoates / Q000378:metabolism*; D003470:Culture Media; D019800:Phenol / Q000378:metabolism*; D011549:Pseudomonas / Q000145:classification* / Q000254:growth & development* / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000254:growth & development / Q000378:metabolism; D044223:Pseudomonas stutzeri / Q000254:growth & development / Q000378:metabolism; D013379:Substrate Specificity
D002723:Chlorobenzoates; D003470:Culture Media; C036427:3-chlorobenzoic acid; D019800:Phenol